The present invention relates in general to heating, ventilating, and air conditioning (HVAC) systems for transportation vehicles, and, more specifically, to personalized control of an HVAC system based on skin temperature of an occupant or driver of the vehicle.
HVAC systems control the climate in transportation vehicles such as automobiles in order to maintain thermal comfort of the vehicle occupants. Typically, a blower passes air through heat exchangers and delivers conditioned air to various points within the passenger cabin. Warm air may be provided by a heater core obtaining heat from coolant flowing in a combustion engine, for example. Cool air may be obtained from a conventional air conditioning system having a motor driven compressor and an evaporator.
The simplest climate control systems in motor vehicles provide the occupant with direct control of the intensity of heating or cooling, the operating speed of the blower, and the relative amount of air flow going to different registers. This requires the user to continually monitor and adjust the climate control settings in order to remain comfortable.
Automatic temperature control systems have also been introduced wherein a feedback control system monitors ambient air temperature within the passenger compartment and automatically adjusts blower speed and heater core or air conditioning operation to maintain a desired temperature setting. In some vehicles, multiple zones have been implemented with separate automatic temperature control with individual target temperature settings being made for each zone.
The foregoing types of HVAC systems only indirectly control the actual skin temperature of an occupant. Because skin temperature is a better indicator of actual occupant comfort, systems have been investigated for regulating HVAC system operation based on the skin temperature of the vehicle occupants. However, the thermodynamic environment in a vehicle interior is complex, as are the relationships between various HVAC control settings and the resulting effect on skin temperature of different occupants. Therefore, previous systems have been relatively complex and not cost effective.